Capabilities ofa Toroid-Amplifier Systemfor Magnetic Measurement ofCurrentin Biological Tissue

Bioelectric current inone-dimensional tissues canbemea- suredbyusing aroomtemperature amplifier andawire-wound, fer- rite-core toroid todetect theassociated biomagnetic field. Inthispa- per,thecapabilities ofsuchatoroid-amplifier system arediscussed, withemphasis placed onthesignal-to-noise ratio andthespatial reso- lution ofthetoroid. Useofthis system formeasuring current isstudied indetail forcardiac andskeletal muscle, andmyelinated andnonmy- elinated nerveaxons. Finally, factors affecting thesensitivity ofopen- abletoroids areconsidered.